Robert Izzard's Pages of Astronomical Happiness


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Robert Izzard's Posters
The Ba Stars Mystery
Tyl Dermine, Robert Izzard, Ross Church and Alain Jorissen
The barium stars are thought to be formed by accretion from a companion AGB star wind. However, this should also circularise their orbits which are observed to be eccentric. We examine two mechanisms for increasing the eccentricity, white-dwarf kicks and circumbinary disks. Both are promising ways to generate eccentricity, but both also have their problems.

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Presented at the Binary Star Evolution: Mass Loss, Accretion and Mergers in Mikonos, June 2010, Asymmetric Planetary Nebulae V, Windermere, England, June 2010 and Why Galaxies Care About AGB Stars II, Vienna, July 2010.
What are the R stars?
Robert Izzard, Simon Jeffery and John Lattanzio
The R Stars are carbon-rich K-giants which should not have their carbon. They are also all single stars so could not have accreted it from a companion. We investigate the number of stars which may form from mergers of white dwarfs and red giants and find that it is compatible with the observed number of R stars.

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Netherlands Astronomy Conference, 2007, Poster prize runner-up!
Galactic Sodium from AGB Stars
Robert Izzard, Brad Gibson and Richard Stancliffe
Galactic chemical evolution models which include sodium from Type II supernovae alone underestimate the abundance of sodium in the interstellar medium, particularly in stars with metallicity up to [Fe/H]=+0.4. We have combined the latest AGB, massive-star and supernova yields in an attempt to resolve the problem.

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Why Galaxies Care About AGB Stars I, Vienna 2006. Poster prize winner!
Window To The Stars
Robert Izzard and Evert Glebbeek
We present our graphical interface to a stellar evolution code Window To The Stars. a poster describing Window To The Stars. Please see the Window To The Stars pages for more information.

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International Astronomical Union General Assembly in Prague and the Netherlands Astronomy Conference in 2006
Metallicity Dependence of Gamma-Ray Burst Progenitors
Robert Izzard, Enrico Ramirez-Ruiz and Christopher Tout
We investigate the binary channel for collapsars and the dependence of its rate on the initial metallicity. The lower the metallicity the less the mass, and angular momentum, lost from the star before it explodes. We find this effect significantly increases the GRB rate.

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Presented at the Canary Islands Winter School Cosmochemistry: The Melting Pot of the Elements in 2001.
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